Power electronics modules are semiconductor modules used in power electronics circuitry. Power electronics modules are employed typically in vehicular, rail and industrial applications, for example in inverters or rectifiers. They likewise find application in the form of energy generation and transmission. The semiconductor components contained in the power electronics modules may involve e.g. semiconductor chips including a Transistor, an insulated gate (IGBT), a metal oxide field-effect transistor (MOSFET), a junction field-effect transistor (JFET), a thyristor, or a diode. These semiconductor components may vary as to their voltage and current handling capacity.
Each of those semiconductor components has a first main electrode, a second main electrode, and a load path formed between the first main electrode and the second main electrode. For instance, the first and second main electrode may be drain and source, source and drain, emitter and collector, collector and emitter, anode and cathode, or cathode and anode, respectively.
Many of those semiconductor components additionally have a control electrode for controlling an electric current through the load path of the respective component. Such semiconductor components are also referred to controllable semiconductor components.
In order to increase the switching capacity, two or more controllable semiconductor components may be arranged in the form of individual semiconductor chips in a common module housing and electrically connected in parallel. To this, the first main electrodes are electrically connected in parallel inside the module housing and connected to at least one common, external first main load terminal. The second main electrodes are also electrically connected in parallel inside the module housing and connected to a common, external second main load terminal. Further, the control electrodes are electrically connected in parallel inside the module housing and connected to a common control terminal. In the sense of the present invention, a terminal is referred to as an “external” terminal if it is arranged outside the module housing.
In addition, each of the controllable semiconductor components, and, accordingly, each of the respective semiconductor chips may be connected at its respective first main load electrode via an auxiliary contact that is used, together with the control electrode of the respective controllable semiconductor chip, for providing that semiconductor chip with a control voltage that serves the control an electric current through the load path. To this, the auxiliary contacts of the semiconductor chips connected in parallel are also connected to one another inside the module housing and connected to a common external auxiliary terminal.
During operation, a control voltage for controlling all parallel semiconductor chips is applied between the external auxiliary terminal and the external control terminal and distributed to the individual semiconductor chips using an arbitrary wiring inside the module housing.
In particular at high currents through the load paths, the electric potential along the wiring that electrically connects the first main load terminals may drop due to the unavoidable ohmic resistance of the wiring. This causes the different semiconductor chips to require different control voltages for being switched on, that is, for switching the respective load paths from an electrically blocking state to an electrically high conductive state.
This however may cause different semiconductor chips not to be commonly and simultaneously switched on or off. In the worst case it may happen that during a switching event in which all semiconductor chips are intended to be commonly switched on or off, some of the semiconductor chips remain in their previous off or on state. As a consequence, the conducting ones of the semiconductor chips, that is, the semiconductor chips in the on state, are required to carry the total current through the module.
Therefore, there is a need for an improved semiconductor module.